Monday, October 8, 2012

The Drivers of Inefficient Medicine

This is a lovely feature piece in the BMJ concisely detailing that surging occult demon consuming healthcare resources under the guise of "improved health" – overdiagnosis.  It's really quite lovely to see the cultural changes coming in medicine, where increasing awareness of costs in the face of questionable benefit will reshape our profession in the years to come.

These authors, from Australia, describe twelve categories of "disease" that are expanding without obvious clinical benefit, as well as a brief overview of the sorts of practices that drive overdiagnosis.  It's a bit of a lead-in to next year's conference, Preventing Overdiagnosis, at Dartmouth University.

The entire article is worth reading, but I thought their table with the drivers of overdiagnosis was a nice summary:

  • Technological changes detecting ever smaller “abnormalities”
  • Commercial and professional vested interests
  • Conflicted panels producing expanded disease definitions and writing guidelines 
  • Legal incentives that punish underdiagnosis but not overdiagnosis
  • Health system incentives favouring more tests and treatments
  • Cultural beliefs that more is better; faith in early detection unmodified by its risks 
"Preventing overdiagnosis: how to stop harming the healthy"

Saturday, October 6, 2012

EMLitofNote on EM:RAP

With Rob Ormon[sic] of ERcast, discussing how (hopefully) coronary CT angiograms don't become as popular as July's discussants propose.

Sorry, I don't have my own readily distributable copy of the clip – but I do have an article coming in a few weeks in EMJ BMJ summarizing my views.

"CT Angio Again!"

Friday, October 5, 2012

Death By Horticulture

This case report, by the surgeons across the street at Baylor, describes a novel cause for bowel obstruction in children.  Apparently, in the course of plant cultivation, it is useful to have water-retaining gel spheres.  Advertised to retain water and grow to 400 times their original size, a child swallowed a "Water Balz" and developed a small bowel obstruction requiring laparoscopy and enterotomy.

More interestingly, the surgeons obtained five of these balls and evaluated their growth pattern.  The balls began life at ~0.95cm in diameter and, after 96 hours, reached a diameter of ~5.5cm, most of the growth in the first 12 hours.  Based on this, the surgeons estimate any swallowed balls would likely easily pass through the pylorus before resulting in complete bowel obstruction.

The claim of growth to 400 times size, however, is unfounded.  The balls they studied only grew to 200 times original size.

"Water-Absorbing Balls: A “Growing” Problem"

Wednesday, October 3, 2012

Trauma, the Hard Way

Anyone who has been to a surgery morbidity and mortality conference understands the cultural bias behind the desire to "pan-scan" all trauma patients.  If an injury is missed, and the body part wasn't scanned, someone is going to need to stand up and look foolish.

However, this article describes a trauma center in Boston that made a concerted effort to reduce CT scanning.  They came up with fifteen evidence-based guidelines for various scans and made a consensus to use these decision instruments to assist in their assessment for need for CT.  And, as you might expect, they identified significant reductions in CT scanning during their study period – 37% total reduction in number of CT scans.  If 37% doesn't sound like a big enough number, perhaps the $1.1M absolute difference in brain, chest, and abdomen/pelvis scan costs is enough to get your attention.

However, they have rather some weaknesses.  They state there were "no missed injuries", which is unusual because every study of CT in trauma patients fails to achieve 100% sensitivity – even in patients with liberal use of CT.  Then, they do have twice as many "complications" in their evidence-based scan group, as well as three times as many 30-day readmissions.  I'm not sure each complication follows from the scanning strategy, but it is an oddly significant difference.

Interestingly, they excluded patients who did not survive 24 hours.  Perhaps it complicated their abstraction process, but it is of slightly greater clinical interest to evaluate for potential missed injuries that resulted in immediate demise, rather than the misses that resulted in slightly longer-term morbidity.

"Evidence-based guidelines are equivalent to a liberal computed tomography scan protocol for initial patient evaluation but are associated with decreased computed tomography scan use, cost, and radiation exposure"

Monday, October 1, 2012

Pediatric Intubation – Not Always Successful

This is an observational study of pediatric medical resuscitation, published in Annals of Emergency Medicine, using video to evaluate the frequency of various adverse events during pediatric intubation.

As expected in a teaching institution, there is a fair bit of variability in initial success rates – ranging from 35% first-pass success for pediatrics residents up to 89% for PEM or anesthesia attendings.  Overall 52% had success on the first attempt.  Unfortunately, 61% experienced at least one adverse event during intubation.  These were typically not clinically important with regard to patient-oriented outcomes.

However,  what is more entertainingly concerning is how few of the complications make it into the medical record.  The written documentation overestimates first-attempt success, underestimates desaturation during the procedure, and even completely omits any mention of one of the two episodes of CPR required during resuscitation.

My guess is that Cincinnati Children's may have had a documentation quality review after this data were collected.

"Rapid Sequence Intubation for Pediatric Emergency Patients: Higher Frequency of Failed Attempts and Adverse Effects Found by Video Review"

Friday, September 28, 2012

"Say Anything", Regardless of the Data

As we've learned from prior publications, the conclusions section of the abstract is the ideal location to "spin" your article to generate news releases.  This article, from JAMA Neurology, compares thrombolysis to endovascular intervention for acute carotid artery occlusions and states "Intravenous thrombolysis should be administered as first-line treatment in patients with early cervical ICA occlusion."

That's a pretty strong statement, without qualifiers.  And, it means it received press coverage from MedPage Today, the ACEP News network, etc.

And, they base that statement on retrospective review of a cohort of 21 patients, 13 of whom received thrombolysis and 8 of whom received endovascular intervention.  The tPA patients did better, done and done, OR for early neurologic recovery 77 (95% CI 3 to 500).  But, then, Table 2 is a mini-systematic review of prior studies – and it turns out the rate of neurologic recovery is more like 40-50% with endovascular treatment, not the 1 in 8 they found in their retrospective cohort.  Indeed, the authors go on to state in the article "These findings are in contrast to the results of previous studies", and have an entirely reasonable, non-conclusive discussion of their findings in context of the other daa.

But, if you want news coverage, say something "interesting" in your abstract.

"Stroke From Acute Cervical Internal Carotid Artery Occlusion"

Wednesday, September 26, 2012

Acetaminophen and Asthma

If this article strikes your fancy – then you'll never look at acetaminophen the same way again.

Published in Pediatrics, this is a bit of a commentary summarizing epidemiological data in both children and adults related to the association between acetaminophen (paracetamol) use and asthma.  Specifically, that there is one, based on the studies he reviews, including:
• A prospective childhood asthma study of 520,000 subjects suggesting a dose-response effect between acetaminophen and asthma in children, up to an increased OR for wheezing of 3.25 for children taking acetaminophen at least once a month.
• A meta-analysis of six pediatric studies with a pooled increased OR for wheezing of 1.95 related to acetaminophen use.
• A meta-analysis of six adult studies with up to an increased OR for asthma of 2.87 for adults taking acetaminophen weekly.

...and several others.  The author does not suggest any specific mechanism through which acetaminophen increases airway reactivity, but he has changed his practice to reduce acetaminophen usage to the minimum.  I can't say I disagree with his hypothesis, and there does appear to be a preponderance of mounting evidence, although I wouldn't say this is an area where I am intimately familiar with the literature.

"The Association of Acetaminophen and Asthma Prevalence and Severity"

Monday, September 24, 2012

Don't Believe The Data

This NEJM study published a couple days ago addresses the effect of funding and methodological rigor on physicians' confidence in the results.  It's a prospective, mailed and online survey of board-certified Internal Medicine physicians, in which three studies of low, medium, and high rigor were presented with three different funding sources: none, NIH award, or industry funding.

Thankfully, physicians were less confident and less likely to prescribe the study drug for studies that were of low methodological quality and were funded by industry.  Or, so I think.  The study authors – and the accompanying editorial – take issue with the harshness with which physicians judge industry funded trials.  They feel that, if a study is of high methodological quality, the funding source should not be relevant, and we should "Believe the Data".  Considering how easy it is to exert favorable effects on study outcomes otherwise invisible to and the "data", I don't think it is safe or responsible to be less skeptical of industry-funded trials.

Entertainingly, their study probably doesn't even meet their definition of high rigor, considering the 50% response rate and small sample size....

"A Randomized Study of How Physicians Interpret Research Funding Disclosures"

Friday, September 21, 2012

The EHR – A Tool For Blocking Admissions

This is a mildly entertaining ethnographic study of how ED physicians, IM physicians, and surgeons used the Electronic Health Record (EHR) in the context of patient care in a tertiary medical center.

Essentially, the authors observed and interviewed residents and attendings in their use of the EHR, and identified its use in a function termed "chart biopsy" during the admission handoff process.  Inpatient teams were observed using the EHR to get a quick overview of the patient prior to the handoff, to provide the foundation for the history & physical, and – most entertainingly – to use as a weapon in negotiation and "blocking" potential admissions with ED physicians.  Other amusing anecdotes include the authors' characterization of inpatient physicians feeling "less 'at the mercy' of ED physicians" after doing a pre-handoff chart biopsy, or feeling as though they could guard against the "disorganized ramblings" off the handoff process.

Overall, the authors correctly identify EHRs as increasingly prevalent supplements to traditional information gathering techniques, and make a reasonable proposal for evolution in EHRs to aid the "chart biopsy" process.

"Chart biopsy: an emerging medical practice enabled by electronic health records and its impacts on emergency department-inpatient admission handoffs."

Wednesday, September 19, 2012

Unnecessary Post-Reduction X-Rays?

Falling into the "well, duh" sort of category that cuts through the dogmatic haze, this article examines the ordering of post-reduction radiographs in the Emergency Department.

Specifically, this group of orthopedists from New York City looks at X-ray utilization and length-of-stay after consultation and management of minimally displaced, minimally angulated extremity fractures.  They note that, of 342 fractures meeting study criteria, 204 of them subsequently received post-splinting radiography.  They note that none of the patients receiving post-reduction radiography had any change in alignment or change in splint application, and this practice resulted in significantly longer ED length-of-stay.

This leads them to their conclusion that minimally displaced, minimally angulated extremity fractures that do not receive manipulation when splinting should not be re-imaged after splint application.  And, this seems like a fairly reasonable conclusion.  It's retrospective, the outcomes are surrogates for patient oriented-outcomes, etc., and it would be reasonable to re-evaluate this conclusion in a prospective trial –   but if your practice is already to not routinely re-image, this supports continuing your entirely reasonable clinical decision-making.

"Post-Splinting Radiographs of Minimally Displaced Fractures: Good Medicine or Medicolegal Protection?"

Monday, September 17, 2012

Longer Resuscitation "Saves"

This article made the rounds a couple weeks ago in the news media, probably based on the conclusion from the abstract stating "efforts to systematically increase the duration of resuscitation could improve survival in this high-risk population."

They base this statement off a retrospective review of prospectively gathered standardized data from in-hospital cardiac arrests.  Comparing 31,000 patients with ROSC following an initial episode of cardiac arrest with a cohort of 33,000 who did not have ROSC – the authors found that patients who arrested at hospitals with higher median resuscitation times were more likely to have ROSC.  Initial ROSC was tied to survival to discharge, where hospitals with the shortest median resuscitation time having a 14.5% adjusted survival compared to 16.2% at hospitals with the longest resuscitations.

Now, if you're a glass half-full sort of person, "could improve survival" sounds like an endorsement.  However, when we're conjuring up hypotheses and associations from retrospective data, it's important to re-read every instance of "could" and "might" as "could not" and "might not".  They also performed a horde of patient-related covariates, which gives some scope of the difficulty of weeding out a significant finding from the confounders.  The most glaring difference in their baseline characteristics was the 6% absolute difference in witnessed arrest – which if not accounted for properly could nearly explain the entirety of their outcomes difference.

It's also to consider the unintended consequences of their statement.  What does it mean to continue resuscitation past the point it is judged clinically appropriate?  What sort of potentially well-meaning policies might this entail?  What are the harms to other patients in the facility if nursing and physician resources are increasingly tied up in (mostly) futile resuscitations?  How much additional healthcare costs will result from additional successful ROSC – most of whom are still not neurologically intact survivors?

"Duration of resuscitation efforts and survival after in-hospital cardiac arrest: an observational study"

Friday, September 14, 2012

How Preposterous News Propagates

Every so often – perhaps more frequently, if you're continuously canvassing the literature – there's a rapturous press release regarding a new medical innovation that seems too good to be true.  And, you wonder, how does the lay media get it so wrong?

This study reviewed a consecutive convenience sample of published literature, looking for articles resulting in press releases.  Then, they looked for elements of the article that made it into the press release, as well as the relative accuracy of the release compared with the overall findings of the article.  Essentially, what they found is that press releases were most likely to have "spin" if the conclusion of the article abstract misrepresented the study findings with "spin".

The authors also have an interesting summary of the sort of "spin" found in abstracts that misrepresent study findings.  These include:

 • No acknowledgment of nonstatistically significant primary outcome
 • Claiming equivalence when results failed to demonstrate a statistically significant difference
 • Focus on positive secondary outcome
 • Nonstatistically significant outcome reported as if they were significant

...and several others.

"Misrepresentation of Randomized Controlled Trials in Press Releases and News Coverage: A Cohort Study"

Wednesday, September 12, 2012

When Positive D-Dimers are Negative

This is the latest article from Jeff Kline, published in Thrombosis and Haemostasis (don't you all subscribe to that, too?), concerning pulmonary embolism and d-Dimer.

Wouldn't it be great if the d-Dimer wasn't a dichotomous cut-off?  Where, if a patient were of sufficiently low pre-test probability, a d-Dimer value that was nearly negative still contributed adequately to a negative likelihood ratio to reduce the probability of a significant pulmonary embolism?  Well, that's the theory behind this article – which looks at d-Dimer measurements combined with age, Wells' score, and Revised Geneva scores.

There are a lot of complex tables in this article breaking down the various potential cut-off values for d-Dimer along with different pre-test probabilities, and the concept presented is that potentially higher cut-off values of d-Dimer can be used without missing PEs larger than sub-segmental.  This is presented in context that a higher cut-off might allow reductions in imaging, which seems fair.

However, the most interesting thing in this article to me is Figure 3 – which is d-Dimer concentration compared with fractional obstruction of pulmonary vascular tree.  It is, unfortunately, pretty clear there's not a great linear relationship between dimer and pulmonary obstruction.  Most low d-Dimers had < 5% obstruction of the vascular tree, but at least one patient with a "negative" d-Dimer had 20% obstruction.  Beyond that, patients were just as likely to have 90% obstruction with modestly elevated d-Dimers than with massively elevated d-Dimers.

"D-dimer threshold increase with pretest probability unlikely for pulmonary embolism to decrease unnecessary computerized tomographic pulmonary angiography"

Monday, September 10, 2012

Not-So Routine Surgery on Dabigatran

This correspondence, published in Blood in March, was probably pretty easy to overlook.

A patient enrolled in RE-LY, the trial comparing dabigatran and warfarin for non-valvular atrial fibrillation, underwent open aortic valve replacement surgery.  As instructed, he discontinued his dabigatran two days prior to the surgery.

Had a little bit of a bleeding problem.

After 26 units of RBCs, 5 packs of platelets, 22 units of FFP, 5 x 10 units of cryoprecipitate, two doses of protamine, two doses of tranexamic acid, and five doses of Factor VIIa, the patient was finally stable enough to be evacuated to the ICU for dialysis to remove the remaining dabigatran.

What's most fabulously ironic about this correspondence is that the authors use this horrifying case to sprightly conclude Factor VIIa and hemodialysis are viable and effective reversal strategies for dabigatran-associated bleeding.

The patient – "The postoperative course was complicated by prolonged ventilation/Enterobacter pneumonia, asymptomatic nonocclusive femoral DVT (by surveillance ultrasonography [postoperative day (POD 7)]), and acute-on-chronic renal failure. Discharge to a rehabilitation facility occurred on POD56." – probably disagrees.

Would you be surprised if I mentioned there's a COI issue involving the authors and the manufacturer?

"Recombinant factor VIIa (rFVIIa) and hemodialysis to manage massive dabigatran-associated postcardiac surgery bleeding"